Assessing the Impact of Land Use Changes and Rangeland and Forest Degradation on Flooding Using Watershed Modeling System

Document Type : Research and Full Length Article


1 Gorgan university of agricultural sciences and natural resources

2 University of Tehran


Extensive flood damages all over the world necessitate its control and operation. Hydrologic impacts of land use change appear in many ways such as total runoff, and flood peak flow. This study was performed in 2014 and aimed to investigate the impacts of land use changes on the occurrence of floods in the catchment of Boostan dam in Golestan province, Iran. For this purpose, Watershed Modeling System (WMS) was used to compare land use areas in 1996 with those in 2006 using the corresponding maps. After the calibration and validation of model in each period, rangeland and forest degradation and its effect on the flooding of catchment were evaluated using two representative parameters of peak flow and volume of flood. Land use maps of both time periods were compared and the achieved results revealed that the total area of rangeland was increased whereas good rangeland areas were decreased, fair rangelands were increased and poor rangeland areas were remained relatively constant that mean a decrease in high quality rangelands in the catchment. Also, the forest areas that decreased intensified flood. But peak flow and flood volume of the whole catchment have been mitigated. In spite of negligible change in total Curve Number (CN) of the catchment, rangelands in downstream and near residential areas converted to the agricultural lands and upstream agricultural lands converted to high and medium density rangeland. This means that distribution of land use changes was in such a way that influential upstream watersheds in flooding were associated with the reduced CNs. So, the implemented biological measures have reduced the flooding potential of the catchment. Sensitivity analysis of the model showed that 5% decrease in CN can cause 40% decrease in peak flow of the catchment and in contrast, 5% increase in CN can enhance flood peak flow up to 60%.


Main Subjects

Ariapour, A., Dadrasi Sabzevar, A. and Toloee, S., 2013. Estimation of Vegetation and Land Use Changes Using Remote Sensing Techniques and Geographical Information System (Case Study: Roodab Plain, Sabzevar City). Journal of Rangeland Science, 4(1), 1-13.
Asharf, A., Naz, R., Wahab, A., Ahmad, B., Yasin, M. and Saleem, M., 2014. Assessment of Landuse Change and Its Impact on Watershed Hydrology Using Remote Sensing and SWAT Modeling Techniques—A Case of Rawal Watershed in Pakistan. International Journal of Agricultural Science and Technology, 2(2): 61-68.
Beiglu, M.J., Hoseini, S.M. and Riahi, S., 2015. The effects of cover and land use change in Tajrish area on discharge regime in Darband River, Jour. Quantitative Geomorphologic Research, 3(3): 95-113. (In Persian).
Brouwer, R. and Van, E.K., 2004. Reintegrated ecological, economic and social impact assessment of alternative flood control policies in the Netherlands. Ecological Economics, 50: 1-21.
Cronshey, R., 1986. Urban hydrology for small watersheds. US Department of Agriculture, Soil Conservation Service, Engineering Division, 1-10.
Gholami, V., Bashirgonbad, M., Ozdi, M. and Jokar, I., 2009. Effect of changes in land use to create runoff and flood risk Kasilian watershed, Jour. Watershed Management Science and Engineering, 3(9): 55-57. (In Persian).
Githui, F., Mutua, F. and Bauwens, W., 2009. Estimating the impacts of land-cover change on runoff using the soil and water assessment tool (SWAT): case study of Nzoia catchment, Jour. Hydrological sciences, 54(5): 899-908.
Hosseini, S. A., Khatir Namany, J. and Akbarzadeh, M., 2012. Studying the Vegetation Changes of Natural Rangelands in Inche Shorezar of Agh Ghala, North Golestan Province, Iran. Journal of Rangeland Science, 2(4): 615-624.
Hosseini, Y., 2012. WMS model assessment in determining the maximum flood discharge in Khuzestan province. Presented at the first national conference on strategies for achieving sustainable development in agriculture, natural resources and the environment, Tehran. (In Persian).
Jajarmizade, M., Hasonizade, H. and Abasi Chenari, S., 2012. Evaluation of Capability of WMS model in watershed simulation and virtual walls’ behavior on geometric simulation accuracy. Presented at the first national conference on sustainable development in arid and semi arid areas, Abarkoh. (In Persian).
Khosroshahi, M. and Saghafian, B., 2005. Routing role of the river in the identification and resolution of flood- prone areas in the watershed. Presented at the fifth Conference on hydraulic, Shahid Bahonar University of Kerman, Iran. (In Persian).
Legates, D. R. and McCabe Jr, G. J., 1999. Evaluating the use of "goodness-of-fit" measures in hydrologic and hydro climatic model validation. Water resources research, 35(1): 233-241.
Meftah Helghi, M., Zanagane, M.E., Karimirad, I., Akhzari, D., Yavarzade, M., 2010. Structural measures on water resources management, watershed Kashydar. Presented at the second national conference on integrated water resources management, Shahid Bahonar University of Kerman. (In Persian).
Miller, S.N., Kepner, W.G., Mehaffey, M.H., Hernandez, M., Miller, R.C., Goodrich, D.C., Devonald, K. D., Heggem, T., Miller, W.P., 2002. Integrating landscape assessment and hydrologic modeling for land cover change analysis, Jour. the American Water Resources Association, 38(4): 915-929.
Nash, J. E. and Sutcliffe, J.V., 1970. River flow forecasting through conceptual models. Discussion of principles. Jour. Hydro, 10(3): 282–290.
Nasri, M., Sarsangi, A. and Yeganeh, H., 2013. Detection of Land Use Changes for Thirty Years Using Remote Sensing and GIS (Case Study: Ardestan Area). Journal of Rangeland Science, 4(1): 23-33.
Razavizade, S., Salajeghe, A., Khalighi Sigarodi, Sh., Jafari, M., 2014. The effect of land use changes on flood characteristics Using HEC–HMS (Case Study: Taleghan watershed), Jour. Range and Watershed Management., 3(66): 373-386. (In Persian).
Rezaee Moghadam, M.H., Andriani, S., Almaspor, F., Valizade Kamran, Kh.,MokhtariAsl, A., 2015. Examine the effects of land use change and land cover on flooding and runoff (Case Study: Alavian Dam watershed), Jour. Hydro geomorphology, 1: 41-57. (In Persian).
Saghafian, B., Farazjo, H., Sepehri, A. and Najafinejad, A., 2006. The effect of land use changes on flooding in watershed Golestan Dam, Jour. Water Resources, 1(2): 18-28. (In Persian).
SCS: national engineering handbook, section 9: hydrologic soil-cover complexes, 2004. Soil conservation service, USDA, Washington, D.C.
Sikka, A.K., Sarma, J.S., Sharda, V.N., Samraj, P., Lakshmanam, V., 2003. Low flow and high flow responses to converting natural grassland into Bluegum (Eucalyptus globulus) in Nilgiris watersheds of south India, Jour. Hydrology, 2(70): 12-26.
Simonovic, S.P., 2002. Two new non-structural measures for sustainable management of floods. Water International, 27: 38-46.
Vahabzade, Gh., Navidi Far, Y., Habibnejad Roshan, M., Abghari, E., 2015. Investigating of the Effect of Land Use Changes on Daily River Discharge Using the HEC-HMS Model (Case study: Ajerloo Watershed, West Azerbaijan Province), Jour. Water and Soil Science, 4(24): 227-236. (In Persian).
Willmott, C. J., 1981. On the validation of models. Physical geography, 2(2): 184-194.
Zadsar, M. and Azimi, M., 2016. Using SWAT Model to Investigate the Impact of Rangeland Management Practices on Water Conservation (Case Study: Gorganroud Watershed, Golestan, Iran). Journal of Rangeland Science, 6(4): 309-319.